Laboratory Report Format#
When writing laboratory reports in CHEM442, students should observe the following rules:
Reports should be written using a word processor (double spaced). Use 1” margins - both sides, top, and bottom.
The language used in reports should be concise and precise. Reports should be written using the third person, simple past tense, passive voice. Do not use personal pronouns. The reports will be graded for spelling, grammar, verb tense and voice, sentence structure, and logic of presentation.
Laboratory reports should be separated into several distinct sections as discussed below. The information from each section should not be mixed up! Each of the sections should be labeled. “Long” reports should include all sections listed below in proper order. “Short” reports will leave out some sections per the table handed out with the tentative experiment schedule, however, declarations made in lab will take precedence (formats can change!).
Each section of the report is designed with a particular purpose in mind. For example, an abstract is often published separately from the rest of the work. It, therefore, must be a report in miniature, clearly stating the problem, the approach, and the results. The remainder of the report should be written as a cohesive package. The theory and necessary equations and formulas are introduced (introduction), the technique and procedures given (experimental), the results presented and discussed in some detail [nauseating?] and conclusions from the results presented (results and discussion). The references and appendix given supporting evidence. This style is similar to that of journal publications in the sciences. For short reports, the introduction and materials and methods sections should not be submitted.
Coverpage#
The coverpage gives the experiment title (be imaginative! DO NOT use title of the separate as your title!), date of report submission, your name and your partners name(s), and your abstract.
Abstract#
An abstract summarizes the principle findings of the work reported in the report and therefore, although it is the first part of the report, logically, the abstract should be written last! The abstract must stand alone and should never refer to other sections of the lab report. It must accurately reflect the content of the paper and should contain the following:
The object of the experiment. Do not write “The object of the experiment …” or “In this experiment it was …” or any similar redundancy.
A solid state fluoride ion (F⁻) selective electrode was used to determine the mass percent fluoride ion in two different commercial toothpaste samples (Pete’s of Vermont Maple, Lot 1498263 and AquaCool Peach Gel, Lot 6 ). In addition, the electrode was evaluated for the analysis by recovery study.
The method used to achieve the objective. Be specific about specialized equipment (‘a Bausch and Lomb Spectronic 20’ not ‘a colorimeter’) and about the actual form of the species used chemically.
A series of standards were prepared over six orders utilizing TISAB for matrix correction. Fluoride was extracted from the toothpaste by boiling the mixture for five minutes. To one sample of each was added 0.100 mmole F⁻ ion. Potentials were measured using an Orion combination electrode (model #: 9609BN) and a FisherBrand pH/mV ion-analyzer (Accumet AP60).
The actual results found.
The maple toothpaste was found to contain 0.145 ± 0.003 % F⁻ (-3.3 % error) with a 96.7 % recovery of the spike. The peach contained 0.064 ± 0.009 % F⁻ (-57%) with a 56.0 % recovery.
A conclusion.
The calibration plot was linear to 4.5 orders of magnitude as predicted by the manufacturer. The electrode was shown to be effective at measuring fluoride content in toothpaste as witnessed by the maple flavored paste with both good accuracy and precision and a high recovery. The effectiveness, however, depends on the sample and perhaps the treatment of the paste or an addition to the TISAB buffer to improve the removal of fluoride ion from the paste matrix.
All abbreviations should be introduced to the reader in both the abstract and the introduction by showing the abbreviation in parens following the full name or word. For example: “… aluminum metal (Al) …”.
Introduction#
The Introduction section should present a general overview of the THEORY behind the experiment to the reader. It should include a brief explanation of the reasoning behind the measurements made in the laboratory. All equations used in writing of the report should be presented and their utility towards reaching the final goal illustrated. Likewise, all pertinent chemical reactions performed in the experiment should be presented and discussed. All equations and reactions should be numbered for easier referencing within the text (as in the separates). All equations and reactions should be separated from the main body of the text using blank lines (also as in the separates). Structures of the main analyte should be shown for organic media along with discussion of their applicable physical properties.
Materials and Methods#
Open with a list in prose form, of all specialized equipment and especially instrumentation including model name and number (e.g. Milton Roy Spectronic 20 Gensys, BU # 091234) and a list of chemicals identifying manufacturer when possible (potassium acid phthalate, Fisher acidimetric standard, Cat # P5-1234). Subsequent paragraphs should summarize the procedure in sufficient detail that another chemist could repeat the experiment. The presentation should be written in prose form, not as an outline. Give a general overview of the experimental steps but do not copy the manual! Refer to the manual where necessary noting deviations announced in lab. Include approximate masses and concentrations, and types of glassware used (this can be done by significant figures: “…measure 25.00 mL …” and “… obtain a 25 mL aliquot … “ and “ … pipet 25 mL of the sample… “ all mean the same thing). Recall that sentences should never begin with a number.
Results and Discussion#
This section presents the results of the experiment using tables and figures (including graphs). The section should begin with a well-written paragraph leading the reader through the maze of tables and figures beyond. All tables should be numbered and titled (e.g. “Table 3: Calculated densities and percent errors”). The figures should be labeled with a figure number, a descriptive caption (do not simply repeat the axis labels), and have axes that are clearly labeled to same number of significant digits as the data was collected. Raw data should not be confused with the results of an experiment. The experimental data sheets containing the raw data should be placed in the appendix section. Following the presentation of the results, this section should also give an explanation of the results with a postulate of the sources of experimental error and a discussion of what the results mean and of what use the experiment was. The discussion will often be shorter but will usually be worth more points because it shows how you thought about and understood the experiment.
Results should be placed in a table using the format:
individual trial data |
experimental mean ± absolute standard deviation (with units) |
relative standard deviation (in ppt) |
true mean (95%) = ### to ### (units) |
Remember to discuss the results. Take a critical view of your values and compare to what is expected!
Important
Post-lab questions are presented in many of the experiments you will perform this semester. You must answer these questions in your discussion.
Conclusion#
What can we conclude about the sample, method, and the instrument in this study? Especially consider how your results compare to theory!
References#
List all references used in the experiment (e.g. the lab manual) and in the writing of the report (textbooks and other sources). Each citation and reference should be numbered for easy reference during report writing.1,2 Proper format includes the author(s),text title, publisher, date of publication, and pages used (if applicable). E.g.
McCurry, D. A.; Hallen, C. P. CHEM442 Lab Manual — Bloomsburg Instrumentation 2024 documentation. https://facstaff.bloomu.edu/dmccurry/instrumentation/chem442/chem442.html (accessed 2024-01-11).
[the lab manual]Skoog, D.A., Holler, F.J., and Nieman, T.A., “Principles of Instrumental Analysis”, 5:sup:th ed, Saunders College Publishing: New York,1998,, pp 105-106.
[a text example]Stanford, J.A. and Justice, J. B. Jr., Analyt. Chem., 1996, 68(11), 359A.
[a journal example]
Tip
You should really use a reference manager. Software exists to keep track of appropriate formatting and number for you. Please speak to your instructor for more details.
Appendices#
Your original experimental values should be presented along with a profusely labeled spreadsheet (Excel, LibreOffice, etc.). Use proper significant figures at all times. These should be contained in the original data sheets from the notebook.
One very common error is to consider the appendix as part of the report and refer to data contained in it. This is in error. If you must refer to the data, it belongs in the Results and Discussion section. Each formal lab report is actually a compilation of three parts: the lab report, a compendium of report called the abstract which is placed before the report but which must be complete enough to stand on its own thus refers to nothing else nor is it referred to, and the appendix which is the communication between you and the instructor showing all the work that you really did thus also is not referred to or from.
Each student should make certain that he or she does his or her own work in writing lab reports. If the grader is convinced that two (or more) individuals people wrote a report and submitted it twice with minor revisions, each student will receive half (or third or fourth…) the average score on the first occurrence. Future repetitions will be scored as a zero. Note also that substantial penalties exist for plagiarism.
The laboratory reports are graded on how well the format was followed, the organization and clarity of the writing, the soundness of the arguments for the conclusions made as well as for grammar, spelling, tense, sentence structure, proper terminology , and the degree of accuracy of any analytical determination where applicable. Neatness does count because the student has ample time to organize and write each report.
If this looks familiar - congratulations! You read it in the 341 lab manual. If not and you made it this far, thanks for reading this time.